Complete the recursive formula of the geometric sequence $300\,,\,60\,,\,12\,,\,2.4,...$. $d(1)=$
Answer: The first term is $300$ and the common ratio is $\dfrac15$. ${\times\dfrac15\,\curvearrowright}$ ${\times\dfrac15\,\curvearrowright}$ ${\times\dfrac15\,\curvearrowright}$ $300,$ $60,$ $12,$ $2.4,...$ This is the recursive formula of $300\,,\,60\,,\,12\,,\,2.4,...$. $\begin{cases} d(1)=300 \\\\ d(n)=d(n-1)\cdot\dfrac15 \end{cases}$